In the fabrication process of semiconductor devices, numerous processing steps must be performed on a semi-conducting substrate to form various circuits. The process may consist of as many as several hundred processing steps. Each processing step is executed in a process chamber such as an etcher, a physical vapor deposition (PVD) chamber, a chemical vapor deposition (CVD) chamber or an ion implanter.
In the vast majority of the processing steps, a special environment of either a high vacuum, a low vacuum, a gas plasma or other suitable chemical environment must be provided for the process. For instance, in a PVD (or sputter) chamber, a high vacuum environment must be provided to surround the wafer such that particles sputtered from a metal target can travel to and to be deposited on an exposed surface of the wafer. In other process chambers, such as in a plasma enhanced chemical vapor deposition (PECVD) chamber, a plasma cloud of a reactant gas or gases is first formed in vacuum over a wafer such that the deposition of a chemical substance can occur on the surface of the wafer. During any processing step, the wafer must also be kept in an extremely clean environment without the danger of being contaminated. The processing of a wafer is therefore always conducted in a hermetically sealed environment that is under vacuum and is completely isolated from the atmosphere. Numerous vacuum process chambers have been provided for such purpose.
A typical vacuum process chamber 10 and its peripheral devices are shown in FIG. 1. The peripheral devices include a vacuum gauge 12 for monitoring the pressure inside the chamber 10, a high vacuum pump 14 connected to the vacuum chamber 10 through an isolation valve 16, conduit 18 and a second vacuum gauge 20 mounted to the conduit 18 through a coupling 22. The peripheral devices further include a rough pump 24 connected to the vacuum chamber 10 through conduit 26 and a shut-off valve 28. A pressure gauge 30 of the thermocouple type is mounted to the conduit 26 for monitoring the pressure. In the vacuum chamber set up of FIG. 1, when the vacuum gauge 12 which is connected to the vacuum chamber 10 through coupling 32 needs to be replaced either for maintenance or for replacement, vacuum must be broken in the vacuum chamber 10. To resume operation of the vacuum chamber after the gauge is replaced, a long pumping time is required for pumping the vacuum chamber to a high vacuum, i.e., to approximately 10.sup.-9 Torr. The long pumping time normally required is between about 10 hours and about 30 hours. Since the vacuum gauge normally needs to be serviced or replaced at an interval of approximately every six months, significant fabrication time is lost and the throughput of the fabrication process is reduced.
It is therefore an object of the present invention to provide a vacuum chamber equipped with a peripheral device mounted on the chamber that does not have the drawbacks or shortcomings of the conventional method for replacing such peripheral device.
It is another object of the present invention to provide a method for replacing a peripheral device on a vacuum chamber that does not require the breaking of vacuum in the chamber.
It is a further object of the present invention to provide a method for replacing a peripheral device on a vacuum chamber by utilizing a device replacement apparatus such that the chamber can be sealed off during the device replacement procedure.
It is another further object of the present invention to provide a method for replacing a peripheral device on a vacuum chamber without affecting the vacuum state in the chamber such that a fabrication process in the chamber can be quickly resumed.
It is still another object of the present invention to provide an apparatus for replacing an attachment on a vacuum chamber without breaking vacuum in the chamber.
It is yet another object of the present invention to provide an apparatus for replacing an attachment on a vacuum chamber without breaking vacuum such that fabrication process in the chamber can be resumed in a short period of time.
It is still another further object of the present invention to provide an apparatus for replacing an attachment on a vacuum chamber that does not break vacuum in the chamber which includes two shut-off valves, a 3-way conduit, a pressure gauge and a rough vacuum pump.
It is yet another further object of the present invention to provide an apparatus for replacing an attachment on a vacuum chamber without breaking vacuum in the chamber such that the down time required for replacing the attachment can be reduced by at least 90%.